As far as chicken mills... unfortunately they are around. There's a local guy who buys birds and takes them to swaps and keeps them in horrible conditions. There are others, too. You can look at the BYC auction page and see pretty quickly who ALWAYS has auctions up for up to ten different breeds.
I think it would be incredibly hard to raise birds responsibly AND earn your living with them.
I for one have several different breeds, all seperated into different pens, to prevent crosses, unless desired.
But I do try to breed to standard and ALWAYS cull lower quality, I have a couple from Knoxville that buys my extra roos and culls, strictly for the table.
I do have a line of Bantams that I call "Barn Yard", I have no ideal of their heritage and do NOT claim them to be good stock, just healthy.
I sure DO NOT make a living off chickens, probably in the last 3 years I have went into the red at least 2000.00.
It would be nice to break even sometimes.
I have purchased birds from the kind of breeders that you are talking about.
Usually I bring them home and keep them awhile and try to make them healthy again.
Mostly, I do this cause I have a soft heart when it comes to abused or neglected animals.
I suppose that is the reason I NEVER go to auctions and hate going to flea markets because there is so many there from "Mills"
I have found some good birds at the FM but it is seldom. As a rule of thumb, if it sounds like a good deal, STAY AWAY.
Good breeders that sell at FM usually DO NOT bring their good stuff and you have to go to their locations to get the good stuff.
There are a few good places to buy. Small animal sales, like the one
TSC of Morristown is having next week.
Actual shows like fairs, but like @
aurissavannahs said there is always someone who sneaks in with sub standard stuff.